Confidence: Medium · Source: FCC ULS · As of 2026-09-14
K4OSI callsign genealogy
Currently held by Johnson, Robert M
The FCC publishes a previous_call_sign on
every amateur license — a self-link to the licensee's prior callsign.
Following those links produces the chain below.
Previous callsigns
Older callsigns held by K4OSI's current licensee, walking backwards.
- Johnson, Robert MTNgranted 2003-12-11cancelled 2004-01-23
Successor callsigns
Callsigns held now by people who previously held K4OSI.
No current licensee on record previously held this callsign.